1. Field of the Invention
The present invention relates to a vibration electric power generator, and in particular to a vibration electric power generator using the electric power generated from vibrations during running of a bicycle.
2. Description of the Background Art
As an electric power generator for a bicycle, a roller dynamo generating electric power by pressing a roller against a tire, and a hub dynamo using an axle as an electric power generator have been conventionally known.
In the roller dynamo, since a roller is pressed against the outer periphery of a tire, a large energy loss is caused due to friction. In contrast, in the hub dynamo, although an energy loss caused due to friction is small, mounting a hub dynamo to a bicycle requires replacement of a wheel.
On the other hand, an electric power generation device generating electric power by linearly moving a movable body having a magnet mounted thereto has been conventionally known.
For example, Japanese Patent Laying-Open No. 2005-151750 (Patent Document 1) describes placing a yoke having a permanent magnet fixed thereto to face an iron core having a coil wound therearound.
Further, Japanese Patent Laying-Open No. 2006-296144 (Patent Document 2) describes a vibration electric power generator in which movable magnets are provided such that north poles (or south poles) thereof face each other with a magnet spacer interposed therebetween.
Furthermore, Japanese Utility Model Registration No. 3121655 (Patent Document 3) describes generating electric power by the action of reciprocating movement produced by vibrations caused during running of a vehicle, and charging the electric power in a battery.
When electric power is generated using pedaling power as in a roller dynamo and a hub dynamo, a loss of energy is caused inevitably. In response to this issue, the inventors of the present application have considered generating electric power using vibrations caused during running of a bicycle.
However, vibrations caused during running of a bicycle cannot necessarily be used effectively for electric power generation by merely applying the configurations described in Patent Documents 1 to 3 to a bicycle. For example, in a linear actuator described in Patent Documents 1 to 3, a space is formed between the magnet and the iron core, and as a result, electromotive force cannot necessarily be obtained sufficiently when the number of vibrations is small and the amplitude of the vibrations is also small.